16-step sequencer from two 4017 decade counters?

[october71]

Hi all,

I'm fairly new here, though I have been reading posts for a while, I finally decided to register and post.

I'm trying to make a 16-step sequencer using the 10-step LED sequencer schematic that's out there which uses the 4017 decade counter IC. I've tried to cascade two 4017s together but the only things I can get it to do are:
1. one 4017 counts ones, the second one counts 10s
2. one 4017 advances one, then the other 4017 advances one (but has both steps on at the same time, which I don't want)
3. both 4017s simultaneously counting ones.

If I can get this thing to sequentially count to 20, I can shorten the steps to 16, which is *exactly* what I want. Help, please!!

Thanks in advance,

 

[Jaw174]

hmm. well you could tryfinding a "flip flop" thingy.. what you need is somethign that will switch thesignal away fom the first 4107 and to the seccond 4017. as how to do that, i ahve no clue Anyone else?

 

[bogdanfirst]

ok, i see this in 2 chioces.
1. you use a binary counter to 16 and a 4 to 16 line decoder.
2. use the 2 4017 with a 4013 flip flop
check the schematic

 

[october71]

Wow, thanks so much! I haven't had a chance to put this together yet because I need a larger breadboard (I have the smallest...and cheapest...one I could get). I'll probably pick another one up tonight or tomorrow and report back

Thanks again!!

 

[Jaw174]

ARg, i was thinkigna flip flop. but i wanst sure so i didnt want to make a fool of myself! hehe

 

[bogdanfirst]

well.....you though of it, and i drew the schematic.
you know what it it will be nice....use 11 4017's to get the same effect with 100 leds.
i would try this, but buying 100 leds is quite expensive......

 

[pebe]

Want another way? I've not tried this but there's a fair chance it will work.
You need 2 - 4017chips, 2 resistors and 2 capacitors.

Wire CLK pins of both ICs together and clock them together.
Wire RESET pins of both chips together. Connect a 100nF from them to Vdd, and a 100K resistor from them to Vss. This ensures reset at switchon.
IC1 - Wire Q9 to CE
Wire 1n cap between IC1 Q8 and CE of IC2, and 22K resistor between CE and Q0 of IC1.

At switchon both ICs reset so Q0 is high. CE of IC1 is low because Q9 is low so count is enabled. CE of IC2 is high (through 100K) so IC2 is disabled.

Clock starts. IC1 counts from 0 thru to Q9. Q9 going high disables further count of that chip. But Q8 going low briefly enables CE of IC2. As CLK is still high at that moment, IC1 will count to Q1. Q0 going low enables IC2 for further counts up to Q9.

So you can count to 17 like this:
IC1 outputs Q1,2,3,4,5,6,7,8 then,
IC2 outputs Q1,2,3,4,5,6,7,8,9

Sorry no diagram - I've not mastered the upload yet!

 

[october71]

hmmm...thanks! I'll give that a try and see how it goes too. I'll let you know once I have it made...

cya,

 

[Jaw174]

what program do you use to make the circuits?

 

[pebe]

I'm trying TinyCad but having difficulty in saving to a format that can be used outside the application.

Is there a better one?

 

[kinjalgp]

I use ExpressSCH ( www.expresspcb.com ). It can export schematic to bitmap.

Even Eagle ( www.cadsoftusa.com ) has this facility.

And both these softwares are free. Eagle has some limitations.

 

[october71]

*sigh*



Ok, I know I must be doing something wrong, and I know it's because there's a couple of things I don't understand about this schematic. I tried making it last night and it wouldn't work at all. The questions I have are this:

1. The areas I've circled with black...does that little square mean that those are connected to ground?

and

2. The areas I circled in blue...what pin on the 4017 is leg #1 of the transistor supposed to attach to?

Sorry if these things should be obvious...I guess I'm not as good at reading schematics as I thought I was

Thanks again,

 

[ljcox]

16 bit sequencer

The use of 2 4017s to create a 16 bit sequencer is rather clumsy.

It would be much more elegant and simpler to use a 4 bit BINARY counter such as the 4516 or 4520 and a binary to 16 line decoder such as the 74C154, 4014 or 4015.

Len

 

[osyrus11]

I agree with len,
or you could try a cd4514.
I had th same problem some time ago.

The place for this is Ray Wilson's DIY synth site.
he's got at least 3 different sets of schematics for various step sequencers, withs all functions explained. Plus, a super helpful guy.
check it out...
(www.musicfromouterspace.com/analogsynth/SEQ16_2006/SEQ16_2006.php)

 

[bfloyd84]

You could also try the Ken Stone designs. I enjoy the Cat-Girl Synth (CGS) 8 step sequencer. Hop over to youtube and look up djthomaswhite. He has a lot of videos on how he made his builds and what not.

 

[bfloyd84]

I agree with len,
or you could try a cd4514.
I had th same problem some time ago.

The place for this is Ray Wilson's DIY synth site.
he's got at least 3 different sets of schematics for various step sequencers, withs all functions explained. Plus, a super helpful guy.
check it out...
(www.musicfromouterspace.com/analogsynth/SEQ16_2006/SEQ16_2006.php)

Some of the boards are either not available or no longer in production. Thats coming from the MFOS site. I too have been wanting to build the MFOS 16 step gate sequencer but haven't been able to get a hold of the boards to do so.

 

[osyrus11]

Some of the boards are either not available or no longer in production. Thats coming from the MFOS site. I too have been wanting to build the MFOS 16 step gate sequencer but haven't been able to get a hold of the boards to do so.

hmmm. surprising. I just ordered them myself quite recently, with no problems. Actually,the design is much like what len suggests below, a 4 bit binary counter with a 16 line collector (the 4514).

 

[Strazdas]

The use of 2 4017s to create a 16 bit sequencer is rather clumsy.

It would be much more elegant and simpler to use a 4 bit BINARY counter such as the 4516 or 4520 and a binary to 16 line decoder such as the 74C154, 4014 or 4015.

Len

Hi guys,

It's rather old post, but I'd like to come back to this issue and ask for help.

I'm building simple step sequencer. Main idea taken from: **broken link removed** . But instead of one 4067 I'm using two 4051 which is more available and cheaper. Schematics are drawn here: **broken link removed** .

Questions are:

1. how to make flip flop (or something else, or some clever cheap solutions) using 4520 Q3 swiching between sequencers, also linking CV's, gates, and reset (is not important). I'd like to have a 2x8 or 1x16 sequencer with independent reset when 2x8 mode in use.
2. Can I connect LED's as shown?


I'm using single +5V power supply and would like to stick to it.

Many thanks, I'm not very into electronics, and clear drawing should be big help for me.

Thanks in advance
Mykolas
Lithuania

 

[MikeMl]

...I'm trying to make a 16-step sequencer using the 10-step LED sequencer schematic that's out there which uses the 4017 decade counter IC. I've tried to cascade two 4017s together...
If I can get this thing to sequentially count to 20, I can shorten the steps to 16, which is *exactly* what

This seems to work. You will have to add a hex inverter to the two 4017s. I',m using two of them as delay pulse stretcher.

The first 4017 counts Q0 to Q8. (nine states). Upon reaching state Q9, it gates off its own clock, and the inverter enables the clock for the second 4017. State Q0 of the first 4017 always resets the second, just to get the two counters in sync. State Q8 of the second counter resets the first counter, and indirectly resets itself. Note that Q0 of the second counter is not used.

 

[YaranAyr]

Well, I'm fresh as a new pack of 555s on this forum. I Googled this 4017 quandary and your post came up. Looks like you've got some good suggestions here. I've thought about this for a few days and did some studying. Here's what I am going to try after Santa delivers my goody bag:
Run a 555 astable clock into a 74LS193 BCD UP-DOWN 16-COUNTER then its 4 BCD OUTS into a 74HC4067 16-CHANNEL MULTIPLEXER. I'll tie the COMMON High (or Low) and have its 16 OUTS run the LEDS (or Sounds or whatever.) So far, the control pins on the 74LS193 look like they will provide flexibilities like cutting the step count to 15, 14, 13, 12, ...., 2. And running backwards, and hopefully running up then back. Of course, we'll see.

How has your project progressed?